The Watchlist can be viewed using either Intraday or End-of-Day data. This is selected using the control on the Watchlist page:

Intraday prices will always show the current session's prices. End-of-Day prices show the previous session's data. The "Time" column indicates when the data was last updated.

For the Intraday view, new price data appear on the page as indicated by a "flash".  

• US equities will show Cboe BZX realtime data for U.S. equities, ET, when available. Volume reflects consolidated markets. 
• All other equities are on a 15-minute delay.
• Futures and Forex symbols are delayed 10 or 15 minutes, CT.

You can set a Watchlist to ALWAYS display using either Intraday or End-of-Day data by using the "Default Data" setting found in the Edit Watchlist page.